Jeroen's Global map has been two coloured blocks all along. Not missing
hydrology, not a missing layer: serve_step_canvas_request zeroed Global's wire
extent, so every request arrived downstream as (0,0), clamped to (1,1), and
resolved to a 2x1 canvas.
That sentinel was correct when Global's size came from the body's region grid
and the client's extent field was meaningless. The D-255 extent inversion made
Global viewport-sized and this line silently outlived it. The commit titled
"size the Global rung to the viewport" was therefore correct and completely
unreachable — its tests passed by calling resolve_canvas_extent directly
rather than through the serve path, i.e. they tested the function that changed
instead of the path the data takes.
Two more places carried the same dead premise, both meaning the first canvas
ever built answered every later request and a resize could never take effect:
- GlobalTierCache keyed on body id alone. Now treats a size mismatch as a
miss, so the re-derive replaces it. Deliberately still ONE entry per body
rather than one per size: keying by size would make a tier that never
evicts accumulate an entry per viewport a player has ever used.
- The client's make_key collapsed Global's extent to a sentinel. Centre
stays collapsed — Global's canvas really is whole-body and origin-anchored
— but extent is now part of the key.
project.yaml 0.4.5 forces the 2x1 canvases already on disk to miss.
Verified through the capture harness, not by reasoning: server probe shows
req=(960,540) radius=6238.4 resolved=960x480, and Ferrath's Global now renders
continents, oceans, inland lakes and polar ice where it previously rendered
one solid rectangle.
Server suite green (45 binaries), client 1830 total / 1804 passed / 26 skipped.
Pair session with Jeroen, 2026-07-27.
Co-Authored-By: Claude <noreply@anthropic.com>
The D-225-discharging wire migration per D-255(c): a new
server/src/atlas/step_canvas.rs subsystem (six-rung StepCanvasRung
ladder — Global variable-extent rung 0 through Chunk 64m — the
StepCanvasRequest/StepCanvasResponse tagged envelope extending the
proven ShapeProbe discriminated-shape pattern, PNG-per-field dense +
MessagePack-native sparse encoding per the T-1179 measured table, and
both server cache tiers: the structurally keep-always GlobalTierCache
and the dual-axis StepCanvasCache with storage TTLs per rung and
SIM_STATE_TTL clock-bucket staleness per the D-227 amendment (1)
formula). Wired through bridge/{mod,tcp,local}.rs (sixth demux shape,
send_step_canvas_response mirroring the five existing senders),
gen_queue.rs (DeriveStepCanvas work item with per-connection-per-rung
coalescing, reusing the shared TerrainAnalysisCache), and plugin.rs
(serve/complete systems, lazy D-206 rung-0 population).
Acceptance gate (mandatory per D-227 amendment (3)):
tests/step_canvas_acceptance_gate.rs — cache-hit == cache-miss
byte-identical for every rung, lossless encode round-trips, cache
round-trips vs fresh derive, distinct-center sanity. 5/5 pass.
Station-spacing cap ADOPTED: course stations floored to District
spacing (2,048 m) at finer rungs — the S2-measured +38-87% chunk/block
course cost had zero display benefit at the same station density
(COURSE_STATION_SPACING_FLOOR_M).
Documented honest gaps, not shortcuts: settlement_id is a proximity
approximation (no footprint polygons exist yet); glaciation/flooded_q
sim-state planes are wire-shape-ready D-253 stubs; rung-0 uses signed
equator-anchored rows (the canonical D-256 core convention — T-1186's
wrong-latitude behavior applies unchanged and unfixed here, by
instruction).
Legacy district_window carrier byte-unchanged: window_derivation_golden
6/6 byte-identical, all district_window suites pass unmodified. Full
suite at implementation time: 2127 passed across 45 binaries.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
jpmschweitzerandClaude